This invention relates generally to the operation of power transformers and, more particularly, to the cooling of power transformers.
The capacity of power transformers, such as mobile power transformers or stationary power transformers located at substations, is impacted greatly by ambient temperature. During the summer, when the demand for electric power is high, ambient temperature can limit substation capacity. Eliminating this seasonal bottleneck will be advantageous for providing uninterrupted service during peak demand periods without having to provide additional transformer capacity to handle the peak loads. While cooling of power transformers is known, conventional systems for providing cooling to power transformers has had only limited effectiveness.
Accordingly, it is an object of this invention to provide a system for cooling power transformers which can cool power transformers more effectively than can conventional power transformer cooling systems.
The above and other objects, which will become apparent to those skilled in the art upon a reading of this invention, are attained by the present invention, one aspect of which is:
A method for cooling a power transformer comprising:
(A) drawing air into a vaporizer having an intake and an exhaust, and passing air through the vaporizer from the intake to the exhaust;
(B) passing liquid cryogen from a storage vessel to the vaporizer, spraying liquid cryogen into the vaporizer, and cooling air within the vaporizer by direct heat exchange with the liquid cryogen; and
(C) passing cooled air from the vaporizer to a power transformer to provide cooling to the power transformer.
A further aspect of the invention is:
A method for cooling a power transformer comprising:
(A) passing air into a cooling device;
(B) cooling the air within the cooling device; and
(C) passing the cooled air from the cooling device to a power transformer to provide cooling to the power transformer.
Another aspect of the invention is:
Apparatus for cooling a power transformer comprising:
(A) a vaporizer having an intake and an exhaust, and having means for drawing cooling fluid into the intake of the vaporizer and for ejecting cooling fluid out from the exhaust of the vaporizer;
(B) a liquid cryogen storage vessel and means for passing liquid cryogen from the storage vessel to the vaporizer; and
(C) a power transformer positioned to be contacted by cooling fluid ejected out from the exhaust of the vaporizer.
Yet another aspect of the invention is:
Apparatus for cooling a power transformer comprising:
(A) a cryogen storage vessel;
(B) a power transformer having a radiator; and
(C) means for passing cryogen from the cryogen storage vessel to the power transformer, said means comprising conduit means having a cryogenic valve and having at least one spray nozzle for spraying cryogen onto the power transformer radiator.
As used herein the term xe2x80x9cindirect heat exchangexe2x80x9d means the bringing of entities into heat exchange relation without any physical contact or intermixing of the entities with each other.
As used herein the term xe2x80x9cdirect heat exchangexe2x80x9d means the transfer of refrigeration through contact of cooling and heating entities.
As used herein the term xe2x80x9ccryogenxe2x80x9d means a fluid which, at atmospheric pressure, is a gas at a temperature of xe2x88x92109xc2x0 F.